This invention relates to a telemeter apparatus for counting a heart rate which transmits by wireless a heart rate detected from a subject using an exercise test system such as a treadmill, to the body of the exercise test system.
In an exercise test system such as a treadmill and an ergometer, a heart beat signal detected from a subject is transmitted by either of a wire system or a wireless system, to a data acquisition apparatus disposed in the exercise test system.
A wire system is used in an ergometer so that a pulse signal obtained from a subject is transmitted through a cable to a data acquisition apparatus.
Two possible systems are the ultrasonic system and the magnetic field system. In the ultrasonic system, electrodes for detecting an electrocardiograph (ECG) and attached to the body of a subject are connected through cables to a transmitter unit which is exposed to a receiver unit of a data acquisition apparatus, and a heart beat signal from the transmitter unit is transmitted in the form of an ultrasonic wave to the receiver. By contrast, in the magnetic field system, a transmitter unit attached to the body of a subject is not required to be exposed to the receiver, and a heart beat signal from the transmitter unit is transmitted through a magnetic field to a a receiver of data acquisition apparatus. The data acquisition apparatus is provided with a sole receiving coil for receiving the heart beat signal transmitted from a transmitting coil of the transmitter unit.
When the wire system is used for leg exercises practiced in an ergometer, etc., no problem will arise. In contrast, it is impossible to detect a pulse wave during the practice of total exercises in a treadmill. Therefore, the wire system is not adequate for the use in a treadmill. If the wire system is used in a treadmill, a pulse wave detected from a subject can be transmitted only during a low speed walking exercise and a pause of an exercise. When the wire system is used in an exercise test system, a cable for signal transmission causes a problem not only in that it is a hindrance to an exercise, but also in that, when this cable moves with the motion of a subject, it easily picks up noise from the background.
The ultrasonic system has problems in that an ultrasonic transmitter unit must be fixedly attached to the body of a subject while being exposed to the receiver, thereby making the attachment to the body cumbersome, and also is that the system is difficult to handle because its size is large. Moreover, the ultrasonic system has a disadvantage that, when something is interposed between the transmitter unit and the receiver unit, it is impossible to conduct data transmission.
In the conventional magnetic field system, since a data acquisition apparatus attached to an exercise test system is provided with only one receiving coil, there arise problems in that the apparatus is susceptible to being affected by noises and that radio interference between adjacent exercise test systems is liable to occur. Conventionally, therefore, it is necessary to separate adjacent exercise test systems from each other by an interval of at least 1.5 m, with the result that the number of exercise test systems which can be juxtaposed on one floor is restricted.